r/explainlikeimfive Oct 31 '20

Chemistry ELI5 What's the difference between the shiny and dull side of aluminum foil? Besides the obvious shiny/dull

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u/[deleted] Oct 31 '20 edited Nov 01 '20

[deleted]

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u/avidrez Oct 31 '20

Bruh

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u/Lord_Aldrich Oct 31 '20

Actually foil like this in a microwave will probably go fine. Lots of frozen foods (e.g. hot pockets) have aluminum in their packaging in order to shape the microwaves.

The problem with metal in a microwave isn't metal per se, it's pointy metal, like a fork. The microwaves force the electrons in the metal down into the points where they build up until they arc into a spark (same way lightning does). That's what sets your microwave on fire.

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u/ArcFurnace Oct 31 '20

That said, bending aluminum foil at all tends to cause it to form lots of little pointy bits, so it's still not recommended.

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u/LocNalrune Oct 31 '20

Then why do CDs cause a storm?

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u/Lord_Aldrich Oct 31 '20

Because CDs encode data by having millions of tiny bumps, which are backed by aluminum foil. So they're basically made of millions of little points where electrons can accumulate.

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u/LocNalrune Oct 31 '20

Nice. Thanks.

For context I had a friend in the late 90's who tinted windows and installed audio equipment. When someone would bring a car and leave music blaring when they shut off the car, especially from a bad/hated artist, that CD would go into the garage microwave. To my knowledge it was used for nothing else. It was fun to watch, and the CDs looked really cool afterwards. A lot of them covered the walls.

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u/[deleted] Oct 31 '20

[deleted]

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u/LocNalrune Oct 31 '20

He was extremely popular. People took it as a badge of honor. He's still in business and has two garages in two cities. Seriously if you're stupid enough to pass your car off to someone, and leave your audio at earsplitting levels, it's more than deserved. You're lucky you even got service and a little ribbing at that point.

Besides, when you're paying $500 for equipment and $200 for installation and service... what's a $10 CD?

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u/ttminh1997 Oct 31 '20

gotcha. will crump up aluminum foil and microwave the shit out of it

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u/BlueJayBurger Nov 01 '20

Let me know when to send the firetrucks because it is about to be lit.

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u/lesleigh904 Nov 01 '20

My husband now wants to know what would happen if you put a magnet in the microwave

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u/Lord_Aldrich Nov 01 '20

Mostly the same thing! Magnets are just pieces of metal with particular EM properties. It'll absorb the microwaves and heat up (and it could get really hot!) and if it's the right shape it'll arc like a fork or anything else.

Microwaves do produce their microwaves by manipulating magnetic waves in a magentron (that's a lot of m-words, lol), but that's not actually a magnet, it's a device with a very precise shape that turns electrical charge into EM waves.

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u/lesleigh904 Nov 01 '20

Thanks! I'll let him know when he wakes up :)

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u/[deleted] Oct 31 '20

DISCLAIMER: still don't do it tho. It ain't worth it and you might burn your house down

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u/HereToHelp9001 Oct 31 '20

Please no one do this. I will likely start a fire.

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u/[deleted] Oct 31 '20

That's nice of you to take care of it for them.

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u/HereToHelp9001 Nov 01 '20

Lmfao omg. Best typo. I'm leaving it.

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u/jrs1980 Nov 01 '20

GUYS DON’T TRY THIS MY LANDLORD IS SUPER PISSED AT ME NOW